I ride Marin/Sonoma almost exclusively, generally a 50 - 70 miler on Saturdays and sometimes longer. I am not sure if we'd be compatible pace wise or not, because I don't really track averages because the terrain varies so much. You can probably get an idea of my riding from here: http://app.strava.com/athlete/training if the link works.
I know Studio Velo has a women's group they're working to promote and also SRCC has rides of all paces and levels. I've been trying to get myself up to one of the SRCC rides as I am a member, but have not had a chance to really do any rides with them.
I don't know any other TE'ers who are in Marin/Sonoma just now but there are plenty in the larger Bay Area who seem willing to come over here to do rides sometimes.